* guests themselves, but it must also access and update the p2m array
* during suspend/resume when all the pages are reallocated.
*
- * The p2m table is logically a flat array, but we implement it as a
- * three-level tree to allow the address space to be sparse.
+ * The logical flat p2m table is mapped to a linear kernel memory area.
+ * For accesses by Xen a three-level tree linked via mfns only is set up to
+ * allow the address space to be sparse.
*
- * Xen
- * |
- * p2m_top p2m_top_mfn
- * / \ / \
- * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
- * / \ / \ / /
- * p2m p2m p2m p2m p2m p2m p2m ...
+ * Xen
+ * |
+ * p2m_top_mfn
+ * / \
+ * p2m_mid_mfn p2m_mid_mfn
+ * / /
+ * p2m p2m p2m ...
*
* The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
*
- * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
- * maximum representable pseudo-physical address space is:
+ * The p2m_top_mfn level is limited to 1 page, so the maximum representable
+ * pseudo-physical address space is:
* P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
*
* P2M_PER_PAGE depends on the architecture, as a mfn is always
* leaf entries, or for the top root, or middle one, for which there is a void
* entry, we assume it is "missing". So (for example)
* pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
+ * We have a dedicated page p2m_missing with all entries being
+ * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
+ * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
*
* We also have the possibility of setting 1-1 mappings on certain regions, so
* that:
* PCI BARs, or ACPI spaces), we can create mappings easily because we
* get the PFN value to match the MFN.
*
- * For this to work efficiently we have one new page p2m_identity and
- * allocate (via reserved_brk) any other pages we need to cover the sides
- * (1GB or 4MB boundary violations). All entries in p2m_identity are set to
- * INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs,
- * no other fancy value).
+ * For this to work efficiently we have one new page p2m_identity. All entries
+ * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only
+ * recognizes that and MFNs, no other fancy value).
*
* On lookup we spot that the entry points to p2m_identity and return the
* identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
* If the entry points to an allocated page, we just proceed as before and
- * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
+ * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
* appropriate functions (pfn_to_mfn).
*
* The reason for having the IDENTITY_FRAME_BIT instead of just returning the
* PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
* non-identity pfn. To protect ourselves against we elect to set (and get) the
* IDENTITY_FRAME_BIT on all identity mapped PFNs.
- *
- * This simplistic diagram is used to explain the more subtle piece of code.
- * There is also a digram of the P2M at the end that can help.
- * Imagine your E820 looking as so:
- *
- * 1GB 2GB 4GB
- * /-------------------+---------\/----\ /----------\ /---+-----\
- * | System RAM | Sys RAM ||ACPI| | reserved | | Sys RAM |
- * \-------------------+---------/\----/ \----------/ \---+-----/
- * ^- 1029MB ^- 2001MB
- *
- * [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100),
- * 2048MB = 524288 (0x80000)]
- *
- * And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB
- * is actually not present (would have to kick the balloon driver to put it in).
- *
- * When we are told to set the PFNs for identity mapping (see patch: "xen/setup:
- * Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start
- * of the PFN and the end PFN (263424 and 512256 respectively). The first step
- * is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page
- * covers 512^2 of page estate (1GB) and in case the start or end PFN is not
- * aligned on 512^2*PAGE_SIZE (1GB) we reserve_brk new middle and leaf pages as
- * required to split any existing p2m_mid_missing middle pages.
- *
- * With the E820 example above, 263424 is not 1GB aligned so we allocate a
- * reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000.
- * Each entry in the allocate page is "missing" (points to p2m_missing).
- *
- * Next stage is to determine if we need to do a more granular boundary check
- * on the 4MB (or 2MB depending on architecture) off the start and end pfn's.
- * We check if the start pfn and end pfn violate that boundary check, and if
- * so reserve_brk a (p2m[x][y]) leaf page. This way we have a much finer
- * granularity of setting which PFNs are missing and which ones are identity.
- * In our example 263424 and 512256 both fail the check so we reserve_brk two
- * pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing"
- * values) and assign them to p2m[1][2] and p2m[1][488] respectively.
- *
- * At this point we would at minimum reserve_brk one page, but could be up to
- * three. Each call to set_phys_range_identity has at maximum a three page
- * cost. If we were to query the P2M at this stage, all those entries from
- * start PFN through end PFN (so 1029MB -> 2001MB) would return
- * INVALID_P2M_ENTRY ("missing").
- *
- * The next step is to walk from the start pfn to the end pfn setting
- * the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity.
- * If we find that the middle entry is pointing to p2m_missing we can swap it
- * over to p2m_identity - this way covering 4MB (or 2MB) PFN space (and
- * similarly swapping p2m_mid_missing for p2m_mid_identity for larger regions).
- * At this point we do not need to worry about boundary aligment (so no need to
- * reserve_brk a middle page, figure out which PFNs are "missing" and which
- * ones are identity), as that has been done earlier. If we find that the
- * middle leaf is not occupied by p2m_identity or p2m_missing, we dereference
- * that page (which covers 512 PFNs) and set the appropriate PFN with
- * IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we
- * set from p2m[1][2][256->511] and p2m[1][488][0->256] with
- * IDENTITY_FRAME_BIT set.
- *
- * All other regions that are void (or not filled) either point to p2m_missing
- * (considered missing) or have the default value of INVALID_P2M_ENTRY (also
- * considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511]
- * contain the INVALID_P2M_ENTRY value and are considered "missing."
- *
- * Finally, the region beyond the end of of the E820 (4 GB in this example)
- * is set to be identity (in case there are MMIO regions placed here).
- *
- * This is what the p2m ends up looking (for the E820 above) with this
- * fabulous drawing:
- *
- * p2m /--------------\
- * /-----\ | &mfn_list[0],| /-----------------\
- * | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. |
- * |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] |
- * | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] |
- * |-----| \ | [p2m_identity]+\\ | .... |
- * | 2 |--\ \-------------------->| ... | \\ \----------------/
- * |-----| \ \---------------/ \\
- * | 3 |-\ \ \\ p2m_identity [1]
- * |-----| \ \-------------------->/---------------\ /-----------------\
- * | .. |\ | | [p2m_identity]+-->| ~0, ~0, ~0, ... |
- * \-----/ | | | [p2m_identity]+-->| ..., ~0 |
- * | | | .... | \-----------------/
- * | | +-[x], ~0, ~0.. +\
- * | | \---------------/ \
- * | | \-> /---------------\
- * | V p2m_mid_missing p2m_missing | IDENTITY[@0] |
- * | /-----------------\ /------------\ | IDENTITY[@256]|
- * | | [p2m_missing] +---->| ~0, ~0, ...| | ~0, ~0, .... |
- * | | [p2m_missing] +---->| ..., ~0 | \---------------/
- * | | ... | \------------/
- * | \-----------------/
- * |
- * | p2m_mid_identity
- * | /-----------------\
- * \-->| [p2m_identity] +---->[1]
- * | [p2m_identity] +---->[1]
- * | ... |
- * \-----------------/
- *
- * where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
*/
#include <linux/init.h>
#include "multicalls.h"
#include "xen-ops.h"
+#define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
+
static void __init m2p_override_init(void);
unsigned long *xen_p2m_addr __read_mostly;
unsigned long xen_max_p2m_pfn __read_mostly;
EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
+static DEFINE_SPINLOCK(p2m_update_lock);
+
static unsigned long *p2m_mid_missing_mfn;
static unsigned long *p2m_top_mfn;
static unsigned long **p2m_top_mfn_p;
-
-/* Placeholders for holes in the address space */
-static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
-
-static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
-
-static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_identity, P2M_MID_PER_PAGE);
-
-RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
-
-static int use_brk = 1;
+static unsigned long *p2m_missing;
+static unsigned long *p2m_identity;
+static pte_t *p2m_missing_pte;
+static pte_t *p2m_identity_pte;
static inline unsigned p2m_top_index(unsigned long pfn)
{
return pfn % P2M_PER_PAGE;
}
-static void p2m_top_init(unsigned long ***top)
-{
- unsigned i;
-
- for (i = 0; i < P2M_TOP_PER_PAGE; i++)
- top[i] = p2m_mid_missing;
-}
-
static void p2m_top_mfn_init(unsigned long *top)
{
unsigned i;
top[i] = p2m_mid_missing_mfn;
}
-static void p2m_mid_init(unsigned long **mid, unsigned long *leaf)
+static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
{
unsigned i;
for (i = 0; i < P2M_MID_PER_PAGE; i++)
- mid[i] = leaf;
+ mid[i] = virt_to_mfn(leaf);
}
-static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
+static void p2m_init(unsigned long *p2m)
{
unsigned i;
- for (i = 0; i < P2M_MID_PER_PAGE; i++)
- mid[i] = virt_to_mfn(leaf);
+ for (i = 0; i < P2M_PER_PAGE; i++)
+ p2m[i] = INVALID_P2M_ENTRY;
}
-static void p2m_init(unsigned long *p2m)
+static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
{
unsigned i;
- for (i = 0; i < P2M_MID_PER_PAGE; i++)
- p2m[i] = INVALID_P2M_ENTRY;
+ for (i = 0; i < P2M_PER_PAGE; i++)
+ p2m[i] = IDENTITY_FRAME(pfn + i);
}
static void * __ref alloc_p2m_page(void)
{
- if (unlikely(use_brk))
- return extend_brk(PAGE_SIZE, PAGE_SIZE);
-
if (unlikely(!slab_is_available()))
return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
*/
void __ref xen_build_mfn_list_list(void)
{
- unsigned long pfn;
+ unsigned long pfn, mfn;
+ pte_t *ptep;
+ unsigned int level, topidx, mididx;
+ unsigned long *mid_mfn_p;
if (xen_feature(XENFEAT_auto_translated_physmap))
return;
p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
}
- for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx = p2m_mid_index(pfn);
- unsigned long **mid;
- unsigned long *mid_mfn_p;
+ for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
+ pfn += P2M_PER_PAGE) {
+ topidx = p2m_top_index(pfn);
+ mididx = p2m_mid_index(pfn);
- mid = p2m_top[topidx];
mid_mfn_p = p2m_top_mfn_p[topidx];
+ ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
+ &level);
+ BUG_ON(!ptep || level != PG_LEVEL_4K);
+ mfn = pte_mfn(*ptep);
+ ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
/* Don't bother allocating any mfn mid levels if
* they're just missing, just update the stored mfn,
* since all could have changed over a migrate.
*/
- if (mid == p2m_mid_missing) {
+ if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
BUG_ON(mididx);
BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
}
if (mid_mfn_p == p2m_mid_missing_mfn) {
- /*
- * XXX boot-time only! We should never find
- * missing parts of the mfn tree after
- * runtime.
- */
mid_mfn_p = alloc_p2m_page();
p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
}
p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
- mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
+ mid_mfn_p[mididx] = mfn;
}
}
/* Set up p2m_top to point to the domain-builder provided p2m pages */
void __init xen_build_dynamic_phys_to_machine(void)
{
- unsigned long *mfn_list;
- unsigned long max_pfn;
unsigned long pfn;
if (xen_feature(XENFEAT_auto_translated_physmap))
return;
xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
- mfn_list = (unsigned long *)xen_start_info->mfn_list;
- max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
- xen_max_p2m_pfn = max_pfn;
- xen_p2m_size = max_pfn;
+ xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
- p2m_missing = alloc_p2m_page();
- p2m_init(p2m_missing);
- p2m_identity = alloc_p2m_page();
- p2m_init(p2m_identity);
+ for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
+ xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
- p2m_mid_missing = alloc_p2m_page();
- p2m_mid_init(p2m_mid_missing, p2m_missing);
- p2m_mid_identity = alloc_p2m_page();
- p2m_mid_init(p2m_mid_identity, p2m_identity);
+ xen_max_p2m_pfn = xen_p2m_size;
+}
- p2m_top = alloc_p2m_page();
- p2m_top_init(p2m_top);
+#define P2M_TYPE_IDENTITY 0
+#define P2M_TYPE_MISSING 1
+#define P2M_TYPE_PFN 2
+#define P2M_TYPE_UNKNOWN 3
- /*
- * The domain builder gives us a pre-constructed p2m array in
- * mfn_list for all the pages initially given to us, so we just
- * need to graft that into our tree structure.
- */
- for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx = p2m_mid_index(pfn);
+static int xen_p2m_elem_type(unsigned long pfn)
+{
+ unsigned long mfn;
- if (p2m_top[topidx] == p2m_mid_missing) {
- unsigned long **mid = alloc_p2m_page();
- p2m_mid_init(mid, p2m_missing);
+ if (pfn >= xen_p2m_size)
+ return P2M_TYPE_IDENTITY;
- p2m_top[topidx] = mid;
- }
+ mfn = xen_p2m_addr[pfn];
- /*
- * As long as the mfn_list has enough entries to completely
- * fill a p2m page, pointing into the array is ok. But if
- * not the entries beyond the last pfn will be undefined.
- */
- if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
- unsigned long p2midx;
+ if (mfn == INVALID_P2M_ENTRY)
+ return P2M_TYPE_MISSING;
- p2midx = max_pfn % P2M_PER_PAGE;
- for ( ; p2midx < P2M_PER_PAGE; p2midx++)
- mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY;
- }
- p2m_top[topidx][mididx] = &mfn_list[pfn];
- }
+ if (mfn & IDENTITY_FRAME_BIT)
+ return P2M_TYPE_IDENTITY;
+
+ return P2M_TYPE_PFN;
}
-#ifdef CONFIG_X86_64
-unsigned long __init xen_revector_p2m_tree(void)
+
+static void __init xen_rebuild_p2m_list(unsigned long *p2m)
{
- unsigned long va_start;
- unsigned long va_end;
+ unsigned int i, chunk;
unsigned long pfn;
- unsigned long pfn_free = 0;
- unsigned long *mfn_list = NULL;
- unsigned long size;
-
- use_brk = 0;
- va_start = xen_start_info->mfn_list;
- /*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long),
- * so make sure it is rounded up to that */
- size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
- va_end = va_start + size;
-
- /* If we were revectored already, don't do it again. */
- if (va_start <= __START_KERNEL_map && va_start >= __PAGE_OFFSET)
- return 0;
-
- mfn_list = alloc_bootmem_align(size, PAGE_SIZE);
- if (!mfn_list) {
- pr_warn("Could not allocate space for a new P2M tree!\n");
- return xen_start_info->mfn_list;
- }
- /* Fill it out with INVALID_P2M_ENTRY value */
- memset(mfn_list, 0xFF, size);
+ unsigned long *mfns;
+ pte_t *ptep;
+ pmd_t *pmdp;
+ int type;
- for (pfn = 0; pfn < ALIGN(MAX_DOMAIN_PAGES, P2M_PER_PAGE); pfn += P2M_PER_PAGE) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx;
- unsigned long *mid_p;
-
- if (!p2m_top[topidx])
- continue;
+ p2m_missing = alloc_p2m_page();
+ p2m_init(p2m_missing);
+ p2m_identity = alloc_p2m_page();
+ p2m_init(p2m_identity);
- if (p2m_top[topidx] == p2m_mid_missing)
- continue;
+ p2m_missing_pte = alloc_p2m_page();
+ paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
+ p2m_identity_pte = alloc_p2m_page();
+ paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ set_pte(p2m_missing_pte + i,
+ pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL));
+ set_pte(p2m_identity_pte + i,
+ pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL));
+ }
- mididx = p2m_mid_index(pfn);
- mid_p = p2m_top[topidx][mididx];
- if (!mid_p)
- continue;
- if ((mid_p == p2m_missing) || (mid_p == p2m_identity))
+ for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
+ /*
+ * Try to map missing/identity PMDs or p2m-pages if possible.
+ * We have to respect the structure of the mfn_list_list
+ * which will be built just afterwards.
+ * Chunk size to test is one p2m page if we are in the middle
+ * of a mfn_list_list mid page and the complete mid page area
+ * if we are at index 0 of the mid page. Please note that a
+ * mid page might cover more than one PMD, e.g. on 32 bit PAE
+ * kernels.
+ */
+ chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
+ P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
+
+ type = xen_p2m_elem_type(pfn);
+ i = 0;
+ if (type != P2M_TYPE_PFN)
+ for (i = 1; i < chunk; i++)
+ if (xen_p2m_elem_type(pfn + i) != type)
+ break;
+ if (i < chunk)
+ /* Reset to minimal chunk size. */
+ chunk = P2M_PER_PAGE;
+
+ if (type == P2M_TYPE_PFN || i < chunk) {
+ /* Use initial p2m page contents. */
+#ifdef CONFIG_X86_64
+ mfns = alloc_p2m_page();
+ copy_page(mfns, xen_p2m_addr + pfn);
+#else
+ mfns = xen_p2m_addr + pfn;
+#endif
+ ptep = populate_extra_pte((unsigned long)(p2m + pfn));
+ set_pte(ptep,
+ pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
continue;
+ }
- if ((unsigned long)mid_p == INVALID_P2M_ENTRY)
+ if (chunk == P2M_PER_PAGE) {
+ /* Map complete missing or identity p2m-page. */
+ mfns = (type == P2M_TYPE_MISSING) ?
+ p2m_missing : p2m_identity;
+ ptep = populate_extra_pte((unsigned long)(p2m + pfn));
+ set_pte(ptep,
+ pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
continue;
+ }
- /* The old va. Rebase it on mfn_list */
- if (mid_p >= (unsigned long *)va_start && mid_p <= (unsigned long *)va_end) {
- unsigned long *new;
+ /* Complete missing or identity PMD(s) can be mapped. */
+ ptep = (type == P2M_TYPE_MISSING) ?
+ p2m_missing_pte : p2m_identity_pte;
+ for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
+ pmdp = populate_extra_pmd(
+ (unsigned long)(p2m + pfn + i * PTRS_PER_PTE));
+ set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
+ }
+ }
+}
- if (pfn_free > (size / sizeof(unsigned long))) {
- WARN(1, "Only allocated for %ld pages, but we want %ld!\n",
- size / sizeof(unsigned long), pfn_free);
- return 0;
- }
- new = &mfn_list[pfn_free];
+void __init xen_vmalloc_p2m_tree(void)
+{
+ static struct vm_struct vm;
- copy_page(new, mid_p);
- p2m_top[topidx][mididx] = &mfn_list[pfn_free];
+ vm.flags = VM_ALLOC;
+ vm.size = ALIGN(sizeof(unsigned long) * xen_max_p2m_pfn,
+ PMD_SIZE * PMDS_PER_MID_PAGE);
+ vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
+ pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
- pfn_free += P2M_PER_PAGE;
+ xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
- }
- /* This should be the leafs allocated for identity from _brk. */
- }
+ xen_rebuild_p2m_list(vm.addr);
+ xen_p2m_addr = vm.addr;
xen_p2m_size = xen_max_p2m_pfn;
- xen_p2m_addr = mfn_list;
xen_inv_extra_mem();
m2p_override_init();
- return (unsigned long)mfn_list;
}
-#else
-unsigned long __init xen_revector_p2m_tree(void)
-{
- use_brk = 0;
- xen_p2m_size = xen_max_p2m_pfn;
- xen_inv_extra_mem();
- m2p_override_init();
- return 0;
-}
-#endif
+
unsigned long get_phys_to_machine(unsigned long pfn)
{
- unsigned topidx, mididx, idx;
+ pte_t *ptep;
+ unsigned int level;
if (unlikely(pfn >= xen_p2m_size)) {
if (pfn < xen_max_p2m_pfn)
return IDENTITY_FRAME(pfn);
}
- topidx = p2m_top_index(pfn);
- mididx = p2m_mid_index(pfn);
- idx = p2m_index(pfn);
+ ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
+ BUG_ON(!ptep || level != PG_LEVEL_4K);
/*
* The INVALID_P2M_ENTRY is filled in both p2m_*identity
* and in p2m_*missing, so returning the INVALID_P2M_ENTRY
* would be wrong.
*/
- if (p2m_top[topidx][mididx] == p2m_identity)
+ if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
return IDENTITY_FRAME(pfn);
- return p2m_top[topidx][mididx][idx];
+ return xen_p2m_addr[pfn];
}
EXPORT_SYMBOL_GPL(get_phys_to_machine);
+/*
+ * Allocate new pmd(s). It is checked whether the old pmd is still in place.
+ * If not, nothing is changed. This is okay as the only reason for allocating
+ * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
+ * pmd. In case of PAE/x86-32 there are multiple pmds to allocate!
+ */
+static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *ptep, pte_t *pte_pg)
+{
+ pte_t *ptechk;
+ pte_t *pteret = ptep;
+ pte_t *pte_newpg[PMDS_PER_MID_PAGE];
+ pmd_t *pmdp;
+ unsigned int level;
+ unsigned long flags;
+ unsigned long vaddr;
+ int i;
+
+ /* Do all allocations first to bail out in error case. */
+ for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
+ pte_newpg[i] = alloc_p2m_page();
+ if (!pte_newpg[i]) {
+ for (i--; i >= 0; i--)
+ free_p2m_page(pte_newpg[i]);
+
+ return NULL;
+ }
+ }
+
+ vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
+
+ for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
+ copy_page(pte_newpg[i], pte_pg);
+ paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
+
+ pmdp = lookup_pmd_address(vaddr);
+ BUG_ON(!pmdp);
+
+ spin_lock_irqsave(&p2m_update_lock, flags);
+
+ ptechk = lookup_address(vaddr, &level);
+ if (ptechk == pte_pg) {
+ set_pmd(pmdp,
+ __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
+ if (vaddr == (addr & ~(PMD_SIZE - 1)))
+ pteret = pte_offset_kernel(pmdp, addr);
+ pte_newpg[i] = NULL;
+ }
+
+ spin_unlock_irqrestore(&p2m_update_lock, flags);
+
+ if (pte_newpg[i]) {
+ paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
+ free_p2m_page(pte_newpg[i]);
+ }
+
+ vaddr += PMD_SIZE;
+ }
+
+ return pteret;
+}
+
/*
* Fully allocate the p2m structure for a given pfn. We need to check
* that both the top and mid levels are allocated, and make sure the
static bool alloc_p2m(unsigned long pfn)
{
unsigned topidx, mididx;
- unsigned long ***top_p, **mid;
unsigned long *top_mfn_p, *mid_mfn;
- unsigned long *p2m_orig;
+ pte_t *ptep, *pte_pg;
+ unsigned int level;
+ unsigned long flags;
+ unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
+ unsigned long p2m_pfn;
topidx = p2m_top_index(pfn);
mididx = p2m_mid_index(pfn);
- top_p = &p2m_top[topidx];
- mid = ACCESS_ONCE(*top_p);
+ ptep = lookup_address(addr, &level);
+ BUG_ON(!ptep || level != PG_LEVEL_4K);
+ pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
- if (mid == p2m_mid_missing) {
- /* Mid level is missing, allocate a new one */
- mid = alloc_p2m_page();
- if (!mid)
+ if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
+ /* PMD level is missing, allocate a new one */
+ ptep = alloc_p2m_pmd(addr, ptep, pte_pg);
+ if (!ptep)
return false;
-
- p2m_mid_init(mid, p2m_missing);
-
- if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
- free_p2m_page(mid);
}
- top_mfn_p = &p2m_top_mfn[topidx];
- mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
+ if (p2m_top_mfn) {
+ top_mfn_p = &p2m_top_mfn[topidx];
+ mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
- BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
+ BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
- if (mid_mfn == p2m_mid_missing_mfn) {
- /* Separately check the mid mfn level */
- unsigned long missing_mfn;
- unsigned long mid_mfn_mfn;
- unsigned long old_mfn;
+ if (mid_mfn == p2m_mid_missing_mfn) {
+ /* Separately check the mid mfn level */
+ unsigned long missing_mfn;
+ unsigned long mid_mfn_mfn;
+ unsigned long old_mfn;
- mid_mfn = alloc_p2m_page();
- if (!mid_mfn)
- return false;
+ mid_mfn = alloc_p2m_page();
+ if (!mid_mfn)
+ return false;
- p2m_mid_mfn_init(mid_mfn, p2m_missing);
+ p2m_mid_mfn_init(mid_mfn, p2m_missing);
- missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
- mid_mfn_mfn = virt_to_mfn(mid_mfn);
- old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
- if (old_mfn != missing_mfn) {
- free_p2m_page(mid_mfn);
- mid_mfn = mfn_to_virt(old_mfn);
- } else {
- p2m_top_mfn_p[topidx] = mid_mfn;
+ missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
+ mid_mfn_mfn = virt_to_mfn(mid_mfn);
+ old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
+ if (old_mfn != missing_mfn) {
+ free_p2m_page(mid_mfn);
+ mid_mfn = mfn_to_virt(old_mfn);
+ } else {
+ p2m_top_mfn_p[topidx] = mid_mfn;
+ }
}
+ } else {
+ mid_mfn = NULL;
}
- p2m_orig = ACCESS_ONCE(p2m_top[topidx][mididx]);
- if (p2m_orig == p2m_identity || p2m_orig == p2m_missing) {
+ p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep));
+ if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
+ p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
/* p2m leaf page is missing */
unsigned long *p2m;
if (!p2m)
return false;
- p2m_init(p2m);
+ if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
+ p2m_init(p2m);
+ else
+ p2m_init_identity(p2m, pfn);
+
+ spin_lock_irqsave(&p2m_update_lock, flags);
+
+ if (pte_pfn(*ptep) == p2m_pfn) {
+ set_pte(ptep,
+ pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
+ if (mid_mfn)
+ mid_mfn[mididx] = virt_to_mfn(p2m);
+ p2m = NULL;
+ }
+
+ spin_unlock_irqrestore(&p2m_update_lock, flags);
- if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig)
+ if (p2m)
free_p2m_page(p2m);
- else
- mid_mfn[mididx] = virt_to_mfn(p2m);
}
return true;
return pfn - pfn_s;
}
-/* Try to install p2m mapping; fail if intermediate bits missing */
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
- unsigned topidx, mididx, idx;
+ pte_t *ptep;
+ unsigned int level;
/* don't track P2M changes in autotranslate guests */
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
return true;
}
- topidx = p2m_top_index(pfn);
- mididx = p2m_mid_index(pfn);
- idx = p2m_index(pfn);
-
- /* For sparse holes were the p2m leaf has real PFN along with
- * PCI holes, stick in the PFN as the MFN value.
- *
- * set_phys_range_identity() will have allocated new middle
- * and leaf pages as required so an existing p2m_mid_missing
- * or p2m_missing mean that whole range will be identity so
- * these can be switched to p2m_mid_identity or p2m_identity.
- */
- if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) {
- if (p2m_top[topidx] == p2m_mid_identity)
- return true;
-
- if (p2m_top[topidx] == p2m_mid_missing) {
- WARN_ON(cmpxchg(&p2m_top[topidx], p2m_mid_missing,
- p2m_mid_identity) != p2m_mid_missing);
- return true;
- }
-
- if (p2m_top[topidx][mididx] == p2m_identity)
- return true;
-
- /* Swap over from MISSING to IDENTITY if needed. */
- if (p2m_top[topidx][mididx] == p2m_missing) {
- WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing,
- p2m_identity) != p2m_missing);
- return true;
- }
- }
+ ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
+ BUG_ON(!ptep || level != PG_LEVEL_4K);
- if (p2m_top[topidx][mididx] == p2m_missing)
+ if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
return mfn == INVALID_P2M_ENTRY;
- p2m_top[topidx][mididx][idx] = mfn;
+ if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
+ return mfn == IDENTITY_FRAME(pfn);
+
+ xen_p2m_addr[pfn] = mfn;
return true;
}
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
- if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
+ if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
if (!alloc_p2m(pfn))
return false;
- if (!__set_phys_to_machine(pfn, mfn))
- return false;
+ return __set_phys_to_machine(pfn, mfn);
}
return true;
#include "debugfs.h"
static int p2m_dump_show(struct seq_file *m, void *v)
{
- static const char * const level_name[] = { "top", "middle",
- "entry", "abnormal", "error"};
-#define TYPE_IDENTITY 0
-#define TYPE_MISSING 1
-#define TYPE_PFN 2
-#define TYPE_UNKNOWN 3
static const char * const type_name[] = {
- [TYPE_IDENTITY] = "identity",
- [TYPE_MISSING] = "missing",
- [TYPE_PFN] = "pfn",
- [TYPE_UNKNOWN] = "abnormal"};
- unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0;
- unsigned int uninitialized_var(prev_level);
- unsigned int uninitialized_var(prev_type);
-
- if (!p2m_top)
- return 0;
-
- for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx = p2m_mid_index(pfn);
- unsigned idx = p2m_index(pfn);
- unsigned lvl, type;
-
- lvl = 4;
- type = TYPE_UNKNOWN;
- if (p2m_top[topidx] == p2m_mid_missing) {
- lvl = 0; type = TYPE_MISSING;
- } else if (p2m_top[topidx] == NULL) {
- lvl = 0; type = TYPE_UNKNOWN;
- } else if (p2m_top[topidx][mididx] == NULL) {
- lvl = 1; type = TYPE_UNKNOWN;
- } else if (p2m_top[topidx][mididx] == p2m_identity) {
- lvl = 1; type = TYPE_IDENTITY;
- } else if (p2m_top[topidx][mididx] == p2m_missing) {
- lvl = 1; type = TYPE_MISSING;
- } else if (p2m_top[topidx][mididx][idx] == 0) {
- lvl = 2; type = TYPE_UNKNOWN;
- } else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) {
- lvl = 2; type = TYPE_IDENTITY;
- } else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) {
- lvl = 2; type = TYPE_MISSING;
- } else if (p2m_top[topidx][mididx][idx] == pfn) {
- lvl = 2; type = TYPE_PFN;
- } else if (p2m_top[topidx][mididx][idx] != pfn) {
- lvl = 2; type = TYPE_PFN;
- }
- if (pfn == 0) {
- prev_level = lvl;
+ [P2M_TYPE_IDENTITY] = "identity",
+ [P2M_TYPE_MISSING] = "missing",
+ [P2M_TYPE_PFN] = "pfn",
+ [P2M_TYPE_UNKNOWN] = "abnormal"};
+ unsigned long pfn, first_pfn;
+ int type, prev_type;
+
+ prev_type = xen_p2m_elem_type(0);
+ first_pfn = 0;
+
+ for (pfn = 0; pfn < xen_p2m_size; pfn++) {
+ type = xen_p2m_elem_type(pfn);
+ if (type != prev_type) {
+ seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
+ type_name[prev_type]);
prev_type = type;
- }
- if (pfn == MAX_DOMAIN_PAGES-1) {
- lvl = 3;
- type = TYPE_UNKNOWN;
- }
- if (prev_type != type) {
- seq_printf(m, " [0x%lx->0x%lx] %s\n",
- prev_pfn_type, pfn, type_name[prev_type]);
- prev_pfn_type = pfn;
- prev_type = type;
- }
- if (prev_level != lvl) {
- seq_printf(m, " [0x%lx->0x%lx] level %s\n",
- prev_pfn_level, pfn, level_name[prev_level]);
- prev_pfn_level = pfn;
- prev_level = lvl;
+ first_pfn = pfn;
}
}
+ seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
+ type_name[prev_type]);
return 0;
-#undef TYPE_IDENTITY
-#undef TYPE_MISSING
-#undef TYPE_PFN
-#undef TYPE_UNKNOWN
}
static int p2m_dump_open(struct inode *inode, struct file *filp)
projects / cascardo / linux.git / blobdiff